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rdf:type |
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lifeskim:mentions |
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pubmed:issue |
4
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pubmed:dateCreated |
2001-9-21
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pubmed:abstractText |
The sarcoplasmic reticulum (SR) Ca(2+) release channel (RyR1) from malignant hyperthermia-susceptible (MHS) porcine skeletal muscle has a decreased sensitivity to inhibition by Mg(2+). This diminished Mg(2+) inhibition has been attributed to a lower Mg(2+) affinity of the inhibition (I) site. To determine whether alterations in the Ca(2+) and Mg(2+) affinity of the activation (A) site contribute to the altered Mg(2+) inhibition, we estimated the Ca(2+) and Mg(2+) affinities of the A- and I-sites of normal and MHS RyR1. Compared with normal SR, MHS SR required less Ca(2+) to half-maximally activate [(3)H]ryanodine binding (K(A,Ca): MHS = 0.17 +/- 0.01 microM; normal = 0.29 +/- 0.02 microM) and more Ca(2+) to half-maximally inhibit ryanodine binding (K(I,Ca): MHS = 519.3 +/- 48.7 microM; normal = 293.3 +/- 24.2 microM). The apparent Mg(2+) affinity constants of the MHS RyR1 A- and I-sites were approximately twice those of the A- and I-sites of the normal RyR1 (K(A,Mg): MHS = 44.36 +/- 4.54 microM; normal = 21.59 +/- 1.66 microM; K(I,Mg): MHS = 660.8 +/- 53.0 microM; normal = 299.2 +/- 24.5 microM). Thus, the reduced Mg(2+) inhibition of the MHS RyR1 compared with the normal RyR1 is due to both an enhanced selectivity of the MHS RyR1 A-site for Ca(2+) over Mg(2+) and a reduced Mg(2+) affinity of the I-site.
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pubmed:grant |
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pubmed:commentsCorrections |
http://linkedlifedata.com/resource/pubmed/commentcorrection/11566777-10021496,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11566777-10412093,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11566777-10473562,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11566777-10590402,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11566777-10733962,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11566777-10790202,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11566777-10839932,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11566777-10922003,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11566777-10942723,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11566777-13441,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11566777-1621949,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11566777-1862346,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11566777-1872369,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11566777-2321964,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11566777-3379071,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11566777-7070707,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11566777-7516645,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11566777-7679249,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11566777-7948678,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11566777-8678899,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11566777-8913591,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11566777-8999838,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11566777-9030597,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11566777-9038826,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11566777-9085308,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11566777-9096063,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11566777-9336187,
http://linkedlifedata.com/resource/pubmed/commentcorrection/11566777-9614063
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pubmed:language |
eng
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pubmed:journal |
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pubmed:citationSubset |
IM
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pubmed:chemical |
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pubmed:status |
MEDLINE
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pubmed:month |
Oct
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pubmed:issn |
0006-3495
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pubmed:author |
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pubmed:issnType |
Print
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pubmed:volume |
81
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
2050-8
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pubmed:dateRevised |
2009-11-18
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pubmed:meshHeading |
pubmed-meshheading:11566777-Animals,
pubmed-meshheading:11566777-Binding Sites,
pubmed-meshheading:11566777-Caffeine,
pubmed-meshheading:11566777-Calcium,
pubmed-meshheading:11566777-Ion Channel Gating,
pubmed-meshheading:11566777-Kinetics,
pubmed-meshheading:11566777-Magnesium,
pubmed-meshheading:11566777-Malignant Hyperthermia,
pubmed-meshheading:11566777-Muscles,
pubmed-meshheading:11566777-Point Mutation,
pubmed-meshheading:11566777-Ryanodine,
pubmed-meshheading:11566777-Ryanodine Receptor Calcium Release Channel,
pubmed-meshheading:11566777-Swine
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pubmed:year |
2001
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pubmed:articleTitle |
Divergent effects of the malignant hyperthermia-susceptible Arg(615)-->Cys mutation on the Ca(2+) and Mg(2+) dependence of the RyR1.
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pubmed:affiliation |
Department Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, USA. balog004@tc.umn.edu
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pubmed:publicationType |
Journal Article,
In Vitro,
Research Support, U.S. Gov't, P.H.S.,
Research Support, Non-U.S. Gov't
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